Spirulan

Previous studies revealed that the sodium spirulan isolated from Spir-ulina platensis consists of 3-linked rhamnopyranosyl, 2-linked 3-O-methyl-rhamnopyranosyl, and 3,4-linked hexuronopyranosyl residues the first unit was sulfated on C-2 or disulfated on C-2 and C-4, and the second one was sulfated on C-4. Recently, Lee et al. [29] evaluated the effect of partial desulfation and oversulfation of this polysaccharide against HSV-1 and HSV-2 (see below). 

The anti-HSV-1 activity of Ca-SP was assessed by plaque yield reduction and compared with those of dextran sulphate as a representative sulphated PS. These data indicate that Ca-SP is a potent antiviral agent against HSV-1, as even at low concentrations of Ca-SP, no enhancement of virus-induced syncytium formation was observed, as occurred in dextran sulphate-treated cultures. Reeently, Lee et al. [73] investigated the effects of structural modifications of Ca-SP on antiviral activity. Calcium ion binding with the anionic part of the molecule was replaeed with various metal cations, and their inhibitory effects on the replication of HSV-1 were evaluated. Replacement of calcium ion with sodium and potassium ions maintained the antiviral activity, while divalent and trivalent metal cations reduced the activity. Depolymerization of sodium spirulan with hydrogen peroxide decreased the antiviral activity as its molecular weight decreased. 

In algae, an example is found in the sulfated polysaccharide spirulan, isolated from the blue-green alga Spirulina platensis, composed of two types of disaccharide repeating-units, O-rhamnosyl-acofriose (3-0-methylrhamnose) and 0-hexosyluronic-rhamnose.226... 

J.-B. Lee, T. Hayashi, K. Hayashi, and U. Sankawa, Structural analysis of calcium spirulan (Ca-SP)-derived oligosaccharides using electrospray ionization mass spectrometry, J. Nat. Prod., 63(2000)136-138. 

A novel sulphated PS named calcium spirulan has been isolated as an antiviral principle from Spirulina platensis (Nordst.) Geitl., a blue-green... 

Hayashi, K., Hayashi, T., and Kojima, I. (1996a). A natural sulfated polysaccharide, calcium spirulan, isolated from Spirulina platensis In vitro and ex vivo evaluation of anti-Herpes simplex virus and anti-human immunodeficiency virus activities. AIDS Res. Hum. Retroviruses 12,1463-1471. 

Hayashi, T., Hayashi, K., Maedaa, M., and Kojima, I. (1996b). Calcium spirulan, an inhibitor of enveloped virus replication, from a blue-green alga Spirulina platensis. ]. Nat. Prod. 59, 83-87. 

Sulfated polysaccharide antibiotic of unknown struct. Composed of two types of repeating disaccharide units O-rhamnosylacofriose and O-hexuro-nosylrhamnose (aldobiuronic acid). Characterised as the Ca deriv. Calcium spirulan, to which CAS no. refers. Isol. from the blue-green alga Spirulina platensis. Antiviral agent. Amorph. powder, (as Ca deriv.). [a]o +14.7 (c, 0.6 in H2O) (Ca deriv.). 

Microbial sources Spirulan-like polysaccharides Arthrospira platensis ( cyanobacterium) inhibition of human cytomegalovirus, herpes simplex virus type 1, human herpesvirus type 6 and human immunodeficiency virus type 1, in-vitro [83] [84] [85] [86]... 

A wide screening to evaluate the antiviral activity of polysaccharide compormds isolated from the cyanobacterium Arthrospira platensis on different viruses was performed by Rechter et al. [83]. These authors reported the results obtained by using specific assays for the quantification of in-vitro viral replication. The polysaccharide fractions, containing spirulan-like molecules, showed a marked inhibition of human cytomegalovirus, herpes simplex virus type 1, human herpesvirus type 6 and human immunodeficiency virus type 1. On the contrary, weak or no inhibition was detected for Epstein-Barr virus and influenza A virus [83]. The in-vitro antiviral activity of polysaccharide calcium spirulan produced by Arthrospira platensis (formerly Spirulina platensis) was previously described [84-86]. 

S. Rechter, T. Konig, S. Auerochs, S. Thulke, H. Walter, H. Dornenburg, C. Wcilter, and M. MarschaU, Antiviral activity of Arthrospira-derived spirulan-like substances. Antiviral Res., 72 (3), 197-206, 2006. 

Rechter S, Konig T, Auerochs S et al (2006) Antiviral activity of Arthrospira-derived spirulan-Uke substances. Antiviral Res 72 197-206... 

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